General information on DWWTS
General information on Domestic Wastewater Treatment systems (including Septic Tank)
Where discharge of domestic effluent or trade effluent to the Irish Water sewerage network is not possible, it will be necessary to provide an on-site wastewater treatment system for residential and commercial developments. In deciding on the location of such systems, Sligo County Council insist that planning applicants and their agents have regard to the protection of the environment and public health and requirements of national planning regulations. In terms of complying with existing planning legislation, it is imperative that advice is obtained from a competent technical professional prior to undertaking works involving the design and installation of a new onsite wastewater treatment system.
Potential Detrimental Impacts
Poor design, installation, management, and maintenance of onsite wastewater treatment systems can result in significant problems including:
- Surface ponding of effluent causing a public health hazard
- Surface water pollution
- Groundwater contamination
- Odour nuisance
- Insects, rodents, and pests that create health problems.
In order to function effectively and to protect public health and prevent water pollution, it is important to ensure that onsite treatment systems are sited, designed, installed, and maintained in accordance with the manufacturer instructions and recommendations and national requirements detailed in the Environmental Protection Agency Code Of Practice on Domestic Wastewater Treatment Systems (P.E ≤ 10) (EPA 2021).
The above document, and associated clarifications issued by the Environmental Protection Agency, is available to view on the Environmental Protection Agency website; www.epa.ie.
For onsite wastewater treatment proposals involving a p.e. in excess of 10, additional advice and guidance is provided in the EPA Wastewater Treatment Manual; Treatment Systems For Small Communities, Business, Leisure Centres And Hotels (EPA 1999).
Additional Guidance is outlined below:
In terms of selection of an onsite wastewater treatment system; The Department of Housing, Planning, Community and Local Government has amended the Technical Guidance Document H (TGD H)- Drainage and Wastewater Disposal, all works involving small wastewater treatment systems will have to comply with the requirements of S.R. 66:2015.
A list of approved/certified systems is available to view at:
Planning permission is required for the installation of a new onsite wastewater treatment system. An application for planning permission must contain sufficient information to ensure the proposed development will be environmentally sustainable. It is a requirement that all planning applications, which include proposals for an onsite wastewater treatment system, are accompanied by an Environmental Protection Agency Site Suitability Assessment, which should be carried out by a competent technical professional (FETAC certified or equivalent). Planning applications involving proposals for use of an onsite wastewater treatment system are assessed by the Environment Section of Sligo County Council, with comments and recommendations forwarded to the Planning Section.
Contact the Environment Section at 071 911 1111.